The BLACKBIRD revisited in BLACKSBURG Presented by Pedro

The BLACKBIRD, revisited in BLACKSBURG. Presented by: Pedro De Oliveira Michael Libeau on April 21, 2000.

Motivation for the project • American intelligence forecasted U-2 vulnerability – Subsonic cruise speed – 70 kft ceiling – 1750 nm range • Improved Russian missile technology plotted (SAM’s) • U-2 being shot down on May 1, 1960 over U. R. S. S. reinforced the idea • Government asked for a new aircraft – low radar cross-section aircraft – Mach 3+ cruising speed (continuous!) – altitudes in excess of 80 kft.

One idea… The SUNTAN Project [Jenkins], p. 6

Another idea. . . Project Oxcart - Archangel II [Jenkins], p. 7

A 12 - the definitive idea [Whitford], p. 188

The U 2 and the SR-71 Drendel p 36

The several versions Drendel 8

SR-71 A General Data • • • Primary function: Strategic Reconnaissance Wing span = 55 ft 7 in (16. 942 m) Length = 107 ft, 5 in (32. 741 m) GTOW = 140, 000 lbf (63, 500 kgf) Engine@Thrust = 2 J 58@32, 500 lbf (65, 000 lbf SLST) Max speed = Mach 3. 31 (World record speed) Rate of Climb = 10, 000+ fpm Ceiling = 85, 069 ft (also a World record) Range = 2, 982 nm at Mach 3, 740 ft, on internal fuel Endurance on internal fuel, at loiter speed= 7 h, At above range 1 h 20 min over target area Manufacturer: Lockheed (Mc. Namara ordered tooling destroyed)

Speed Comparison (“faster than a rifle bullet”) • Mig-25 engines reported being destroyed after flying at 3. 2 M. Unofficial maximum speed was 2. 8 M • XB-70 only dashed at 3. 2 M - most of the flight was subsonic. • The SR-71 used to fly at 3. 0 M+ for hours.

Thrust-to-Weight Ratio Comparison • The Mig-25 fuselage has a much smaller fineness ratio. Jane’s, 74/75

Wing-Loading Comparison

More on T/W x W/S Comparison MIG-25 SR-71 XB-70 Concorde [Whitford], p. 39

Wing Geometry Comparison Speed increase demands thinner wings. [Whitford], p. 30

Speed increase also demands larger turn radii. [Jenkins], p. 93

Aerodynamic Considerations Another application of the KISS methodology • High fineness ratio bodies • Highly swept double-delta wing. [Whitford], p. 188

Aerodynamic Considerations - FUSELAGE • • High fineness ratio for minimum wave drag Use of chines: – better directional stability: reduction of the side-force – offset the backward movement of the A. C. with Mach number [Whitford], p. 150

Aerodynamic Considerations - WING • • Double-delta plan form allows high (t/c) ratio to minimize wave drag Swept keeps most of the wing in Mach cone : – For Mach 3. 0 flight – SR-71 wing sweep angle: • Conical camber – moves the center of lift inboard – relieves loading on engine nacelle structure due to outboard wing – reduction in high rolling moment due to sideslip inherent to highly swept wings [Whitford], p. 188

Aero Considerations - VERTICAL TAILS • • All moving tails (+20/-20 deg) Cant angle to – reduce induced rolling moment when dr ≠ 0 – stay on the correct side of the vortices shed by the nacelles - reduced VT deflection at low speed with ≠ 0 Whitford, p. 195

Vortices - I Crickmore p 66

Vortices - II Crickmore p 181

The all-moving VTs. Crickmore p 44 Drendel p 20

Stable or unstable? Drendel p 45

YF-12 needed improved directional stability Drendel p 12 Drendel p 17

Fins must fold for landing. Drendel p 15

Aero Considerations - Aerodynamic Heating • The SR-71, a hot airplane: – 600 F at nose (aerodynamic heating at Mach 3+) – 520 F at the windshield glass – 1200 F at the exhaust nozzle (fuel burned) • • 93% of the structural weight built of Titanium alloys Cord-wise corrugations on wing skin The utility of the black paint (lower temps. , lower RCS) Nitrogen both in tires and in fuel tank

Aero Considerations - Aerodynamic Heating • • • Fuel used also as coolant JP-7, a high-flashing point fuel Fuel leakage always a problem Special hydraulic fluids (powders? ) to operate at 600 F Special tires, retracted into the fuselage fuel tank area

Fuel leakage always a problem Air&Space Magazine, Feb/Mar 99, vol. 13 (6)

Propulsion: Turbojet or Ramjet? • At Mach 3 cruise, turbojet engine makes only 17% of total thrust AIAA-69 -757, p. 7

Turbo-ramjet: a hybrid propulsion system AIAA-69 -757, p. 7

Flow must decelerate from supersonic to subsonic before the compressor first stage http: //www. airspacemag. com/asm/mag/supp/fm 99/oxcart. html

Missions • • Reconnaissance (it should be RS, Pres. Johnson turned it SR) Interceptor (YF-12) Mother-ship Research Vehicle

Typical Reconnaissance Mission Crickmore p 69

A modern ship, but also a mother-ship. Jenkins p 50

The mother-ship delivery. Jenkins p 44

SR-71 in High Speed Research • NASA Dryden currently is conducting high speed flight research using two SR-71 aircraft. • Excellent platforms to carry out research and experiments in a variety of areas (aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies and sonic boom characterization) • Data from the SR-71 high-speed research program will be used to aid designers of future supersonic/hypersonic aircraft and propulsion systems, including a high-speed civil transport.

NASA’s SR-71 and A-12 http: //www. dfrc. nasa. gov/Projects/SR 71/home. html

Bye-bye, Blackbird. [Jenkins], p. 85

One airplane, several names • • A(rchangel)-12 Blackbird Cygnus Habu Senior Crown SR-71 as Strategic Reconnaissance, but also. . . YF-12

Reference List • Burrows, William E. , “The Oxcart Cometh, ” Air&Space Magazine, Vol. 13 (6), Smithsonian Institution, Washington, D. C. , Feb. /Mar. 1999. • Crickmore, Paul F. , “LOCKHEED SR-71 – The Secret Missions Exposed, ” BAS Printers Limited, Great Britain, 1993. • Drendel, Lou, “SR-71 Blackbird in action, ” Squadron/Signal Publications, Inc. , Carrolton, TX, 1982. • “Jane’s All the World Aircraft” from years 68/69, 69/70, 74/75. • Jenkins, Dennis R. , “SR-71/YF-12 BLACKBIRDS”, WARBIRDTECH series, vol. 10, Specialty Press Publishers and Wholesalers, 1997. • Johnson, Clarence L. , “Some Development Aspects of the YF-12 A Interceptor Aircraft, ” AIAA Paper No. 69 -757, 1969. • Whitford, Ray, “Design for Air Combat”.